# Brownian motion -- an example of a NON multi-threaded Tkinter program ;)
# By Michele Simoniato, inspired by brownian.py
from tkinter import *
import random
import sys
WIDTH = 400
HEIGHT = 300
SIGMA = 10
BUZZ = 2
RADIUS = 2
LAMBDA = 10
FILL = 'red'
stop = 0 # Set when main loop exits
root = None # main window
def particle(canvas): # particle = iterator over the moves
r = RADIUS
x = random.gauss(WIDTH/2.0, SIGMA)
y = random.gauss(HEIGHT/2.0, SIGMA)
p = canvas.create_oval(x-r, y-r, x+r, y+r, fill=FILL)
while not stop:
dx = random.gauss(0, BUZZ)
dy = random.gauss(0, BUZZ)
try:
canvas.move(p, dx, dy)
except TclError:
break
else:
yield None
def move(particle): # move the particle at random time
particle.next()
dt = random.expovariate(LAMBDA)
root.after(int(dt*1000), move, particle)
def main():
global root, stop
root = Tk()
canvas = Canvas(root, width=WIDTH, height=HEIGHT)
canvas.pack(fill='both', expand=1)
np = 30
if sys.argv[1:]:
np = int(sys.argv[1])
for i in range(np): # start the dance
move(particle(canvas))
try:
root.mainloop()
finally:
stop = 1
if __name__ == '__main__':
main()
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